The category defining multi-use belay/rappel devices from Petzl. This variation of this type of device strikes one of the best balances between function, ease-of-use, and lightweight for many types of all around climbers.  Different modes allow you to vary the amount of friction and stopping power for use with a variety of ropes of different diameters, and for rappelling and lowering.  Easily belay either off of your harness or directly off of a solid anchor.  A lead climber can belay a seconding climbing partner directly off of a solid anchor, and then transfer the device to their harness when swapping leads to be able to rig the device to belay their climbing partner who will lead the next pitch without having to re-feed the climbing rope through the device.  A lead climber also has the ability to belay one or two seconding climbers simultaneously off of a solid anchor. This device also includes an auto-block release hole that accepts a carabiner for use in the "Reverso" belay mode whenever it is necessary to "un-lock" the device and give slack when it is under tension from a seconding climber while the lead climber is belaying that seconding climber directly off of a solid anchor.